The recent threat of Ebola, pandemic influenza A/H5N1, the SARS epidemic, the global HIV epidemic, and growing resistance to antimicrobial drugs, along with the bioterrorist events following September 11, 2001, highlighted the need for a general capacity to rapidly detect, characterize, and control both known and unknown agents. As the need to address infectious disease threats grows, the number of disciplines relevant to doing so has exploded. The combination of computational power and Big Data of various forms provides a new opportunity to study infectious diseases and their transmission through a wide variety of novel approaches, necessitating a new level of sophistication in the training of infectious disease epidemiologists. We recognize the need for a corps of academic and government epidemiologists, ideally working in concert to boost capacity both in peacetime and during crises. The time is not far off when the toolbox of the infectious disease epidemiologist will include sophisticated approaches to causal inference, transmission-dynamic modeling (both mathematical and agent-based), model fitting using Monte Carlo and other Bayesian techniques, population genomics and phylogenetics, and other techniques that are currently cutting-edge. The goal of Harvard School of Public Health's Interdisciplinary Program in Infectious Disease Epidemiology (IPIDE) through this submission of our competitive renewal, is to increase the number of graduates who will be capable of drawing on these diverse tools in a knowledgeable way to meet the infectious disease threats of a new generation. Our training faculty includes leading practitioners of all of these techniques and our recent graduates are emerging with deep training, research experience, and publications in many of these areas. In the past funding period, we have supported 4 - 5 pre-doctoral candidates per year in epidemiologic research methods through formal training at the Harvard School of Public Health. The training program includes coursework in epidemiology, drug resistance, and mathematical modeling of disease from the Interdisciplinary Concentration in Infectious Disease Epidemiology (hsph.harvard.edu/idepi) under the close supervision of our 27 faculty mentors, leading either to a DSc or a PhD. Harvard's IPIDE has been running successfully for fifteen years, and this training grant has helped develop not only a new cadre of students with the capacity to monitor, prevent, and suppress diverse emerging infectious diseases while pursuing a variety of biomedical career options in both the public and private sectors, but has also allowed IPIDE to expand its faculty, funding, diversity of research, and, the number of students who join the infectious disease epidemiology program. Over the past ten years, 26 trainees have been supported, 22 graduated, and they published 436 peer-reviewed manuscripts (297 in infectious disease epidemiology). For the current submission, we are proposing to support 4, increasing to 7 pre-doctoral students each year over the next five-year project period.